bonjour
f ( -5) = - 2 et f ( 4) = - 5
( - 5 + 2 ) : ( 4 + 5 ) = - 3 /9 = - 1 /3
ax = - x /3
f ( -5) = - 2
- 5 * - 1/3 + b = - 2
⇔ 5/3 + b = - 2
⇔ b = - 2 - 5/3 = - 11 /3
f (x) = - x /3 - 11 /3
f ( 4 ) = - 5
4 * - 1/3 - 11 /3 = - 4/3 - 11 /3 = - 15 /3 = - 5
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